Tongqing Zhang

and 14 more

The Asian Clam (Corbicula fluminea) is a valuable commercial and medicinal bivalve that is widely distributed in East and Southeast Asia. As a natural nutrient source, the clam is high in protein, amino acids, and microelements. In China, C. fluminea plays an important role in the diversity of freshwater ecosystems. The genome of C. fluminea has not yet been characterized, therefore, genome-assisted breeding and improvements cannot yet be implemented. In this work, we present a de novo chromosome-scale genome assembly of C. fluminea using PacBio and Hi-C sequencing technologies. The assembled genome comprised 4,728 contigs, with a contig N50 of 521.06 Kb, and 1,215 scaffolds with a scaffold N50 of 70.62 Mb. More than 1.51 Gb (99.17%) of genomic sequences were anchored to 18 chromosomes, of which 1.40 Gb (92.81%) of genomic sequences were ordered and oriented. The genome contains 38,841 coding genes, 32,591 (83.91%) of which were annotated in at least one functional database. Compared with related species, C. fluminea had 851 expanded gene families and 191 contracted gene families. The expanded genes were significantly enriched in 9 terms associated with metabolite synthesis. The phylogenetic tree showed that C. fluminea diverged from the ancestors of marine bivalves ~492.00 million years ago (Mya). Additionally, we identified two MITF genes in C. fluminea and several core genes involved in vitamin B6 metabolic pathways. The high-quality and chromosomal Asian Clam genome will be a valuable resource for a range of development and breeding studies of C. fluminea in future research.